Legalizing marijuana was so last week. A new Boston Herald poll finds Massachusetts voters favor legalizing recreational weed by a margin of 53-37 percent.

But Philip Seymour Hoffman’s overdose has put the question of heroin in a new light. As Gene Robinson, among others, notes, what killed Hoffman wasn’t ignorance of heroin’s dangers, or lack of access to rehab services. And it wasn’t heroin per se. An autopsy is pending, but the culprit appears to be problems with either purity or dosing. An old, but useful, saw says “the poison is in the dose.” People don’t overdose accidentally on prescription drugs because they have been certified for purity and the instructions for how much to take for the desired effect are printed on the label. We don’t get that with street drugs. Make heroin legal and there will still be an addiction problem, but there would be fewer people killed by overdoses.

As I noted in a recent editorial, we seem to have entered a new phase in the drug debate. Elected officials alarmed by the rash of heroin casualties aren’t talking about more cops and tougher sentences. They are talking about harm reduction and more access to treatment. That’s a good thing.